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Study On Yb3+-doped Passively Mode-locked Fiber Laser

Posted on:2008-07-02Degree:MasterType:Thesis
Country:ChinaCandidate:X F ZhouFull Text:PDF
GTID:2178360245491895Subject:Physical Electronics
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Fiber lasers with rare-earth-element fiber as the gain medium have more advantages over semiconductor laser and traditional solid laser .It has already become one of hottest topics in the field of the ultrashort pulse laser research . On the basis of our laboratory facilities and a research project, this thesis work was focused, experimentally and theoretically, on a thorough research on an Yb3+-doped fiber laser for generating ultrashort pulses. The main contents of the dissertation are as follows:I. The basic theory of the mode-locked fiber laserEmploying the rate equations while omitting the ASE, expressions of the Yb3+-doped fiber laser's threshold value, slope efficiency and output power have been deduced .The characteristics of the Yb3+-doped fiber laser pumped by a 976nm-laser have been simulated numerically. Relations between the performance parameters and structure parameters have also been studied .The obtained results show that the performance parameters of the laser are obviously affected by the structural parameters . The choice of the structural parameters has significant influence on the optimization of the laser.II. Ring cavity mode-locked Yb3+-doped fiber laser1. Starting from the time-domain mode-locking master equation, we analyzed the mechanism of fast saturable absorber for obtaining ultrashort pulses and fully discussed the influences of bandwidth , cavity losses, dispersion on the fiber laser .2. Exploiting the nonlinear polarization rotation technique and adjusting the polarization controllers'orientations and pump power, we achieved stable operations of Q-switched, Q-switched mode-locked and CW mode-locked regimes in a ring cavity Yb3+-doped fiber laser.III. Linear cavity mode-locked Yb3+-doped fiber laser with a saturable absorber.For the first time, exploiting a SESAM as a slow saturable absorber and the nonlinear polarization rotation effect as a fast saturable absorber, the Q-switched mode-locked and CW mode-locked pulse trains were obtained in a line cavity mode-locked Yb3+-doped fiber laser.
Keywords/Search Tags:mode-locking, SESAM, Yb3+-doped fiber, Q-switched, Q-switched mode-locked
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